A technology of a conventional in-vehicle electronic control device having a CPU monitoring function is disclosed in Patent Documents 1 and 2, for example. This technology adopts a lockstep system as the above-mentioned monitoring function, which has a collation circuit for collating the processing results of two information processing units: systems A and B, each having an identical configuration. If the collation results from the collation circuit do not agree with each other, either system A or B is determined inoperative
Moreover, a configuration having two different CPUs: a control CPU and a monitoring CPU for the above-mentioned monitoring function and adopting a system that the control CPU is monitored by the monitoring CPU has been adopted (e.g., see Patent Document 3).